For more than a year, the Obama administration has been assuring the world that the downfall of Syrian dictator Bashar al-Assad is “a matter of time.” Yes, its own Middle East experts warned, but how much time matters. The longer the fighting goes on, they said, the more likely it is that what began as a peaceful mass opposition movement would be hijacked by extremists, including allies of al-Qaeda.

President Obama ignored that advice, ruling out measures that could have quickly brought down the regime — such as a no-fly zone — in favor of a year of feckless diplomacy. But it turned out the experts were right. So now the consequence of Obama’s passivity has a name, one that will surely haunt the occupant of the White House in 2013: Jabhat al-Nusra.

Jackson Diehl is deputy editorial page editor of The Post. He is an editorial writer specializing in foreign affairs and writes a biweekly column that appears on Mondays. View Archive

Actually, the full name of the Middle East’s latest jihadist terror movement, announced on an al-Qaeda-linked Web site last January, is Jabhat al-Nusra li-Ahl al-Sham Min Mujaheddin al Sham fi Sahat al Jihad, which means “Support Front for the People of Syria from the Mujaheddin of Syria in the places of Jihad.” It was dismissed at first as a hoax, or maybe as a concoction of Assad’s intelligence service. Now its black flag is recognized, and often cheered, across Syria, and its bearded, baggy-pantalooned fighters are at the forefront of the critical battle for the city of Aleppo.

In the spring Jabhat al-Nusra had maybe 50 adherents, most of them in hiding, and had claimed credit for only a handful of attacks. Now it may have close to 1,000 core followers, and fighting units around Syria have begun openly claiming to belong to it. On YouTube, videos show the residents of areas taken over by the rebels waving its flag and chanting its name.

“They have been able to take an extremist identity and really give it a popular following in a context of bloody civil war,” says Elizabeth O’Bagy, the author of a sobering study of Syria’s jihadists for the Institute for the Study of War. “They have become the most significant threat to long-term stability in Syria.”

No, Barack Obama’s policies alone did not create this monster. It is, first of all, a creature of Assad’s own regime, blowback from his years of sponsoring terrorist networks in Lebanon, Iraq and the Palestinian territories. For more than a decade, Syrian intelligence allowed al-Qaeda and other jihadist groups to establish bases and logistical networks to support attacks on American troops in Iraq, anti-Syrian politicians in Lebanon, and Israel. Now many of those rat lines have been reversed, and the extremists are targeting Assad.

They do so because they were never his natural allies — Assad’s Alawite sect, an offshoot of Shiite Islam, is considered heretical by the Sunni jihadists — and because they see an opening to rebuild a movement that was shattered in Iraq and Afghanistan.

One of the first contingents to bolster Jabhat al-Nusra, O’Bagy found, came from Fatah al Islam, a former Syrian intelligence client that launched a battle in 2007 to take over a Palestinian refu­gee camp near Tripoli, Lebanon. “These individuals,” O’Bagy writes, “received training in weapons and insurgency tactics from the Syrian government and gained experience using them in Iraq and Lebanon. They also have knowledge of and connections to the Syrian intelligence and security apparatus.”

In fact, the group has specialized in attacks on intelligence facilities. On Oct. 9, it staged a sophisticated, three-stage assault on an air force intelligence compound outside Damascus. Earlier in the month, it claimed credit for a string of bombings in Aleppo that targeted an officer’s club and other government-held facilities, reportedly killing dozens.

Leaders of the Free Syrian Army, the mainstream rebel force that emerged from the original protest movement, don’t support the jihadists or their tactics. But as the war in cities like Aleppo becomes more desperate, Jabhat al-Nusra has provided precious reinforcements. Thanks to generous support from sources in Saudi Arabia and other Persian Gulf states, its units are often better-armed than secular forces, which have been starved by Obama’s ban on U.S. weapon supplies.

The result, says O’Bagy, is that the character of Syria’s opposition has changed. “It’s no longer a pro-democracy force trying to bring down a dictatorship. It no longer holds the moral high ground. They have muddied the waters.”

If the war drags on, Jabhat al-Nusra will surely grow stronger. It could begin to carve out a haven in the Syrian countryside where al-Qaeda operatives from around the region could gather. It could try to get hold of Syria’s abundant stocks of chemical weapons. And it could start looking beyond Syria for targets. You might say it’s a matter of time.

Comments our editors find particularly useful or relevant are displayed in Top Comments, as are comments by users with these badges: . Replies to those posts appear here, as well as posts by staff writers.

To pause and restart automatic updates, click "Live" or "Paused". If paused, you'll be notified of the number of additional comments that have come in.

Comments our editors find particularly useful or relevant are displayed in Top Comments, as are comments by users with these badges: . Replies to those posts appear here, as well as posts by staff writers.